Bilateral anterior acetabular-superior pubic ramus junction fatigue fractures in a marathon runner.

Fatigue fractures occur due to repetitive submaximal mechanical stress on bone and are most common in the lower extremities of endurance athletes and military recruits. This report details a rare case of bilateral anterior acetabular-superior pubic ramus junction fatigue fractures in a marathon runner presenting with low back and hip pain. MR imaging of the pelvis was initially interpreted as normal. Further review by a sports medicine physician and a musculoskeletal radiologist prompted an addendum identifying bilateral mild marrow edema of the anterior acetabula with incomplete fracture line on the left and near complete fracture line on the right. Multiple factors may have contributed to the initial missed diagnosis, including the rarity of the stress fracture location and symmetry, the subtlety of the imaging findings, and the atypical clinical presentation often associated with pelvic stress fracture development. Additionally, the patient's infection with SARS-CoV-2 prior to fatigue fracture formation may have played a pathologic role due to muscular deconditioning as well as disrupted bone metabolism. The subacute fracture pattern described in this report should be recognized by radiologists on MR imaging to avoid the potentially debilitating consequences of progression and exacerbation of fatigue fractures in endurance athletes.